Universities must investigate measures, including random dope testing, to tackle the increasing use of cognitive enhancment drugs by students for exams, a leading behavioural neuro­scientist warns.

Student use of drugs, such as Ritalin and modafinil, available over the internet and used to increase the brain's alertness, had "enormous implications for universities", said Barbara Sahakian, a professor of clinical neuropsychology at Cambridge University's psychiatry department.

Normally prescribed for neurological disorders including Alzheimer's disease, attention deficit hyperactivity disorder (ADHD) and narcolepsy, such drugs boost acetylcholine in the brain, improving alertness and attention. Their use has prompted concerns that they could give students an unfair advantage. "This is something that universities really have to discuss. They should have some strategy, some kind of active policy," Sahakian said.

"The coercion aspect is a strong one. Some students say they feel it is cheating, and it puts pressure on them to feel they have to use these drugs when they don't really want to."

Sahakian, whose work is at the forefront of research on the effects of such drugs on healthy people, said urgent debate was now needed on the ethics of how society dealt with "smart drugs".

Though data on long-term effects on healthy users was not yet available, some scientists believe that pharmaceutical advancement and ­cultural acceptance could make ­"cosmetic neurology" as popular as beauty "enhancements".

"If a safe and effective drug is developed which enhances cognition, then I think it would be difficult not to allow access to it," Sahakian said. But if such drugs were then legal, many ethical issues had to be addressed.

Speaking before a lecture at the Royal Institution tomorrow on the ethical implications of smart drugs for universities and schools, she added: "The big question is, are we all going to be taking drugs in the next 10 years and boosting our cognition in that way?

"And if we are, will we use them to have a shorter working week, so we can go home, spend more time with our families and have a good work/life balance? Or, will we go headlong into a 24/7 society where we work all the time because we can work all the time?

"You have to consider there are things that could be beneficial about such drugs because we have an ageing population: people may have to work for longer, and their pensions may not be performing. It may be, as you get older, that people may want to take a cognitive enhancement drug."

Surveys in the United States indicate that 16% of university students are using "smart drugs". There are global websites and chatrooms devoted to how to best use drugs to aid study.

Most buy the drugs over the internet. "That is a real concern, because they are not aware of what they are ­getting, or how it could affect them," Sahakian said.

A Nature magazine poll of 1,400 respondents – mostly scientists and researchers – indicated that one in five had used "smart drugs". Questioned about their attitude towards use, the majority frowned on their use in competitive situations, such as university entrance exams. However, some admitted that they would feel under pressure to give their child a "smart" drug if other children were using them.

"If these drugs become, essentially, legal, it will be difficult to say you can't use them for a competitive exam," Sahakian said. "Students who don't use them feel this is cheating. This is something that universities should at least discuss. Should there be urine testing? These questions have to be looked at."